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Click here to see animation of DNA replication to help you visualize this dynamic process!
(Please note: You must view this animation-and any animation in this tutorial-using an Adobe Shockwave plugin which can be downloaded from http://www.adobe.com/shockwave/download/download.cgi.)
The process of DNA replication in all organisms is amazing, but in humans it seems particularly difficult to conceive. The sum of all genes in a human cell-the human genome-is estimated to be approximately 3 billion base pairs, and a single DNA chain might contain up to 250 million pairs of bases. What's even more incredible is how few mistakes are made in this process despite the immense size of human DNA! An error occurs only about once in each 10-100 billion bases. As you would probably expect, the complete process of DNA replication in human cells takes several hours. To replicate such huge molecules as human DNA at this speed requires not one, but many replication forks, forming replication bubbles and producing many segments of DNA strands that eventually meet up together and are joined to form the newly synthesized double helix.
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